Hi Mark

Marc responded to your questions!
I just wanted to add one thing that is often missed and rarely
discussed about water flow.

There is a natural current already existing in an aquaria, if you live
in North America it flows counterclockwise. If you live in Australia
the natural flow is clockwise. As such, one should not try to defeat
mother nature and force the natural flow in the opposite direction.

The larger your aquaria the more pronounced mother nature's hold is!

TTUL
Gary